// SPDX-License-Identifier: GPL-2.0 /* * R-Car PWM Timer driver * * Copyright (C) 2015 Renesas Electronics Corporation * * Limitations: * - The hardware cannot generate a 0% duty cycle. */ #include #include #include #include #include #include #include #include #include #include #include #define RCAR_PWM_MAX_DIVISION 24 #define RCAR_PWM_MAX_CYCLE 1023 #define RCAR_PWMCR 0x00 #define RCAR_PWMCR_CC0_MASK 0x000f0000 #define RCAR_PWMCR_CC0_SHIFT 16 #define RCAR_PWMCR_CCMD BIT(15) #define RCAR_PWMCR_SYNC BIT(11) #define RCAR_PWMCR_SS0 BIT(4) #define RCAR_PWMCR_EN0 BIT(0) #define RCAR_PWMCNT 0x04 #define RCAR_PWMCNT_CYC0_MASK 0x03ff0000 #define RCAR_PWMCNT_CYC0_SHIFT 16 #define RCAR_PWMCNT_PH0_MASK 0x000003ff #define RCAR_PWMCNT_PH0_SHIFT 0 struct rcar_pwm_chip { void __iomem *base; struct clk *clk; }; static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip) { return pwmchip_get_drvdata(chip); } static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data, unsigned int offset) { writel(data, rp->base + offset); } static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset) { return readl(rp->base + offset); } static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data, unsigned int offset) { u32 value; value = rcar_pwm_read(rp, offset); value &= ~mask; value |= data & mask; rcar_pwm_write(rp, value, offset); } static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns) { unsigned long clk_rate = clk_get_rate(rp->clk); u64 div, tmp; if (clk_rate == 0) return -EINVAL; div = (u64)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE; tmp = (u64)period_ns * clk_rate + div - 1; tmp = div64_u64(tmp, div); div = ilog2(tmp - 1) + 1; return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE; } static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp, unsigned int div) { u32 value; value = rcar_pwm_read(rp, RCAR_PWMCR); value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK); if (div & 1) value |= RCAR_PWMCR_CCMD; div >>= 1; value |= div << RCAR_PWMCR_CC0_SHIFT; rcar_pwm_write(rp, value, RCAR_PWMCR); } static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns, int period_ns) { unsigned long long one_cycle, tmp; /* 0.01 nanoseconds */ unsigned long clk_rate = clk_get_rate(rp->clk); u32 cyc, ph; one_cycle = NSEC_PER_SEC * 100ULL << div; do_div(one_cycle, clk_rate); tmp = period_ns * 100ULL; do_div(tmp, one_cycle); cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK; tmp = duty_ns * 100ULL; do_div(tmp, one_cycle); ph = tmp & RCAR_PWMCNT_PH0_MASK; /* Avoid prohibited setting */ if (cyc == 0 || ph == 0) return -EINVAL; rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT); return 0; } static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { return pm_runtime_get_sync(pwmchip_parent(chip)); } static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { pm_runtime_put(pwmchip_parent(chip)); } static int rcar_pwm_enable(struct rcar_pwm_chip *rp) { u32 value; /* Don't enable the PWM device if CYC0 or PH0 is 0 */ value = rcar_pwm_read(rp, RCAR_PWMCNT); if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 || (value & RCAR_PWMCNT_PH0_MASK) == 0) return -EINVAL; rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR); return 0; } static void rcar_pwm_disable(struct rcar_pwm_chip *rp) { rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR); } static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip); int div, ret; /* This HW/driver only supports normal polarity */ if (state->polarity != PWM_POLARITY_NORMAL) return -EINVAL; if (!state->enabled) { rcar_pwm_disable(rp); return 0; } div = rcar_pwm_get_clock_division(rp, state->period); if (div < 0) return div; rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR); ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period); if (!ret) rcar_pwm_set_clock_control(rp, div); /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */ rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR); if (!ret) ret = rcar_pwm_enable(rp); return ret; } static const struct pwm_ops rcar_pwm_ops = { .request = rcar_pwm_request, .free = rcar_pwm_free, .apply = rcar_pwm_apply, }; static int rcar_pwm_probe(struct platform_device *pdev) { struct pwm_chip *chip; struct rcar_pwm_chip *rcar_pwm; int ret; chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*rcar_pwm)); if (IS_ERR(chip)) return PTR_ERR(chip); rcar_pwm = to_rcar_pwm_chip(chip); rcar_pwm->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(rcar_pwm->base)) return PTR_ERR(rcar_pwm->base); rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(rcar_pwm->clk)) { dev_err(&pdev->dev, "cannot get clock\n"); return PTR_ERR(rcar_pwm->clk); } chip->ops = &rcar_pwm_ops; platform_set_drvdata(pdev, chip); pm_runtime_enable(&pdev->dev); ret = pwmchip_add(chip); if (ret < 0) { dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret); pm_runtime_disable(&pdev->dev); return ret; } return 0; } static void rcar_pwm_remove(struct platform_device *pdev) { struct pwm_chip *chip = platform_get_drvdata(pdev); pwmchip_remove(chip); pm_runtime_disable(&pdev->dev); } static const struct of_device_id rcar_pwm_of_table[] = { { .compatible = "renesas,pwm-rcar", }, { }, }; MODULE_DEVICE_TABLE(of, rcar_pwm_of_table); static struct platform_driver rcar_pwm_driver = { .probe = rcar_pwm_probe, .remove = rcar_pwm_remove, .driver = { .name = "pwm-rcar", .of_match_table = rcar_pwm_of_table, } }; module_platform_driver(rcar_pwm_driver); MODULE_AUTHOR("Yoshihiro Shimoda "); MODULE_DESCRIPTION("Renesas PWM Timer Driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:pwm-rcar");